ARP head studs: supplied assembly lube or LocTite in block?

[62Ranchero200]

Greetings Ranchero Fans,

For those of you who have used ARP head studs, did you use the ARP-supplied assembly lube, or Loctite in the threaded holes in the block? I realize that the hole that threads into the water jacket requires thread sealer.

Thanks
Bob the Builder

 

[CNC-Dude]

You should never use LocTite on the studs, it will make disassembly 100% more difficult if you need to remove the head. Just use a silicone based thread sealer and you'll be fine. The ARP lube is for putting on the threads for the nuts and washers to be lubricated, not the block threads.

 

[62Ranchero200]

You should never use LocTite on the studs, it will make disassembly 100% more difficult if you need to remove the head. Just use a silicone based thread sealer and you'll be fine. The ARP lube is for putting on the threads for the nuts and washers to be lubricated, not the block threads.

So you install ARP head studs with the block threads dry? As I understand it, thread sealer is only used for the head studs that penetrate the water jacket.

Without LocTite, the studs won't back out when you attempt to loosen the nuts if you remove the head?

Thanks
Bob

 

[CNC-Dude]

You should never use LocTite on the studs, it will make disassembly 100% more difficult if you need to remove the head. Just use a silicone based thread sealer and you'll be fine. The ARP lube is for putting on the threads for the nuts and washers to be lubricated, not the block threads.

So you install ARP head studs with the block threads dry? No, as I mentioned, you put a silicone sealer on all of them.As I understand it, thread sealer is only used for the head studs that penetrate the water jacket.

Without LocTite, the studs won't back out when you attempt to loosen the nuts if you remove the head? I think you are trying to overthink this portion of it, LocTite will almost ruin the studs if you have to ever remove them, because you will have to use vice grips to remove them, marring up the shanks of the studs, and it just isn't necessary to use it for this application.

Thanks
Bob

 

[rbohm]

8) i wouldnt use loctite on head studs, but i would use blue loctite on main studs.

 

[CobraSix]

First, if ARP supplied the assembly lube, use it.

As CNC said, NEVER use loctite on the head studs. If you properly torque a bolt or stud, there is enough clamping force to create sufficient friction between the threads that the bolt won't back out. The reason you should use assembly lube (or some other oil) is so you can actually get to the proper torque. Without the lube, if there is any dirt at all on the threads (either the stud or the block) you will get a false torque reading due to the friction caused by the debris. The goal of the torque setting is to pretension the stud using the strength of the material, not the friction on the threads. This is how you get proper clamping force, especially on heads. It's also the same reason that studs are preferable to bolts. Loctite can actually cause the stud to give a false torque reading due to the friction and can lead to blown head gaskets if you didn't get the properly clamping force achieved. Sure, the loctite will get the stud from moving, but that's not the purpose of the head stud.

There are times and places for loctite. If the bolt is just merely trying to hold something in place without a lot of load (aka, the volvo wheel bearing retainer piece that I hate so much to replace), loctite is not a bad idea, but even then I rarely if ever use it. But for items on engine assembly, where the studs and bolts are there to hold pieced together with tight tolerances, I never use loctite. Assembly lube or engine oil only on the threads. I want the torque to come from the pretensioning and not friction. Silicon isn't bad as it does have some lube properties while wet. Downside is on removal, cleaning the threads will take a little more time (the threads in the block as well).

Regards,